System and method for using printed documents

ABSTRACT

A system and method for using specially printed paper and a handheld device to supplement, or replace, large displays and user interfaces commonly required for efficient use of computing devices. The paper is encoded with location information and a message. The message is distributed redundantly across the page, may be arbitrarily large, and may contain security information. In one embodiment, the device uses a single sensor to read the encoded message and location information, and to measure the relative motion of the device. After scanning the specially printed paper, a user may then raise the device, place it on any convenient flat surface, and continue to slide, exploring areas outside of the printed copy.

BACKGROUND

The design of displays for computing devices is always a compromise. Ifthe display is large, then the device is too expensive, and too large,to be practical. If the display is small, then too little informationcan be displayed at once. Thus, when viewing large documents, users canonly view a small portion at any one time, and must often manipulatecontrols to adjust the visible portion—looking first at one part, thenat another. This works, but is inefficient.

Printed documents are easier to read than most computer displays. Theycan be much larger and have higher resolution than computer displays.They can also be navigated quickly—for example, a salesperson familiarwith the company catalogue can very quickly locate the page where anitem of interest is described. However, printed documents have thedisadvantage that they are static, and often out-of-date.

One way of interacting with a printed paper is described by Anoto AB, asubsidiary of C Technologies AB of Sweden. They print special paperforms, which have a specific address printed in each 2 mm×2 mm squaresection. The Anoto™ system uses a pen with a built-in camera thatrecognizes the printed pattern. If a user writes on the paper with thispen, the pen reads the addressing information, and sends the addressesto a server. The server forwards the pen's recorded motion to the entitythat has leased/purchased the identified portion of the fixed addressspace. For example, suppose Filofax Group Limited purchases a section ofthe address space for e-mail purposes. A user could then buy e-mailpaper from Filofax®. When the user writes on the e-mail paper and checksthe “send” box, the pen sends its recorded movements (a list of theaddresses on the page over which it passed) to the Anoto™ server. Theserver looks up the addresses, sees that they were leased to Filofax,and forwards the recorded movements to that company's server. TheFilofax server then translates the pen's motion into an electronicmessage, e.g., e-mail, and then e-mails it to the user.

A disadvantage of the Anoto™ system is that the encoded address is of afixed size. Each location on one of their printed pages corresponds toan absolute location in a 60 million km² grid. This works well forprinted forms (where a small section of the address can be repeatedlyused on thousands of identically-printed documents), but it doesn'tallow for user-printed documents. Further, the Anoto™ system patternsmust be printed on a high resolution printer at approximately 1000 dpito fit the whole address into a 2 mm×2 mm square. Also, the system usesthe combination of pen/printed paper only as an input device, and themethod they employ can only provide positional information while the pencan see the paper. It does not provide a means to display up-to-dateinformation to the user, and if you slide off the edge of the page, itstops working.

Several mechanisms are presently available for encoding an address onprinted media that identifies the printed document or points to anaddress, i.e., Uniform Resource Identifier (URI). For example, one couldprint a barcode, or other identifying mark, on the document. Then onecould read the barcode, recall the document, and then explore it using apointing device (such as a mouse).

One can also use printed bar codes to serve as input devices. Forexample, in a store, the clerk can scan a printed bar code, rather thanhaving to manually type an item number. It is even possible to encodelarge amounts of information in printed marks, and then extract it byscanning. Examples include the dataglyph developed by Xerox Corporation,and the digital watermark system developed by Digimark.

While there are numerous devices and methods for interacting withprinted documents, there is a need for devices and mechanisms whichallow the printed document to replace both large keyboards, and largedisplay devices, in a very natural way.

SUMMARY

It is desired to combine the benefits of a computer display (providingimmediate access to up-to-date information) with the benefits of a paperdocument (providing a large, high-resolution display area). It is alsodesirable to use printed documents to provide large amounts ofrelatively static information, while using computing devices to providerelatively small amounts of up-to-date information.

Furthermore, is would be desirable to use the same printed documents tosupplement the input mechanisms on the computing device, so that thecombination of the printed document and the small device serves as areplacement both for a large display, and a large keyboard.

An embodiment of the present invention uses specially printed paper tosupplement, or replace, the large displays and user interfaces commonlyrequired for efficient use of computing devices. An embodiment providesa method which requires only a single sensor and which supports a widerange of operations. It is shown that a combination of a small computingdevice, and a printed page, can be as efficient as a full sized computerwith a large display and keyboard.

An embodiment of the present invention overcomes the disadvantages ofthe prior art by providing, on a printed page, an encoded message in away so that multiple copies are distributed across the whole page and sothat the message has an arbitrarily large size. In that way, the messagemay be unique to every new document that is printed and may include afull web address and/or security features. Since the message appears inmultiple locations, the whole message may be obtained, even if parts ofthe document are missing. Both the message and the absolute location areencoded in the same way, so they can be read with a single image sensor,and with a single motion of the sensor over the paper.

Furthermore, the same sensor may be used to detect the relative motionof the device. As the sensor moves, it may use images of the surfacebelow to detect relative motion. By comparing its measured relativemotion, with the absolute position information encoded on the page, itis able to calibrate its motion sensor to the page, and may thencontinue to provide relative location information even when the sensoris slid past the edge of the paper. In this way, the user may navigatebeyond the bounds of the real paper document.

In an exemplary embodiment, the combination of a handheld device and aspecially printed page are used to plan a road trip. In this case, theprinted page appears as a map to the human user, but contains bothencoded location information, and a message instructing a handheldscanning device that it is a map, and how to interpret the locationdata. The handheld device includes a graphical display which may betransparent or opaque, and an image sensor on the underside. The imagesensor is used both to read the encoded information and to detectrelative motion of the device. As the user slides a PDA (personaldigital assistant, or other portable device) across the map, it extractsthe message, and begins to show details of the cities/sights related tothe region of the printed page beneath it. To plan the trip, they moveover sights of interest and press a “select” button when each is in thedisplay. In this way, the combination of the printed page and thehandheld device is used to quickly enter large amounts of information ina very natural way. When done, they slide to a region of the map onwhich is printed “plan my route”. The PDA then plans the route, anddisplays it. If the user wishes, they can now view the route by slidingback over the map—on the screen they see the map below, with their routeoverlaid on top. In this way, the combination of the printed page andthe handheld device is also serving as a replacement for a huge display.The user may then leave the printed map behind, and still manipulate theon-screen map, merely by sliding the hand-held device on any convenientflat surface.

DESCRIPTION OF DRAWINGS

An exemplary embodiment of the invention is illustrated in the drawingsin which like numeral references refer to like elements, and wherein:

FIG. 1 is a representation of a printed page encoded with an addressaccording to an embodiment of the present invention;

FIG. 2 is an illustration of a printed sales by region map as might beused in an application of an embodiment of the present invention;

FIG. 3 is an illustration of an application of an embodiment of thepresent invention where a personal digital assistant acts as amagnifying glass for a printed sales region map document;

FIG. 4 is an illustration of a calendar page as might be used in anapplication of an embodiment of the present invention;

FIG. 5 is an illustration of an application of an embodiment of thepresent invention where a personal digital assistant acts as amagnifying glass for a printed calendar document;

FIG. 6 is a block diagram showing a system according to an embodiment ofthe invention; and

FIG. 7 is a flow diagram showing the method of an embodiment of thepresent invention.

DETAILED DESCRIPTION

The numerous innovative teachings of the present application will bedescribed with particular reference to the presently preferred exemplaryembodiments. However, it should be understood that this class ofembodiments provides only a few examples of the many advantageous usesof the innovative teachings herein. In general, statements made in thespecification of the present application do not necessarily delimit anyof the various claimed inventions. Moreover, some statements may applyto some inventive features but not to others.

In an exemplary embodiment of the present invention, the system includesa printed page containing encoded information, a hand-held scanningdevice which can both read the encoded information and detect relativemotion, a computing device (with access to a storage device) which canperform operations in response to the encoded information and measuredmotion, and display and user interface components for additionalinteraction with the user.

The information encoded on the printed page includes both a digitalmessage, and absolute location information. These may be encoded byprinting a set of dots on the page. In some aspects of the invention,the dots are invisible to the naked eye. One method for encoding themessage and absolute location is to print the dots by moving them veryslightly away from a perfect position. The amount and direction that thedot is moved away from that perfect position is the way information isencoded. An alternative way to print the dots is by printing dots andknown spaces, such that a blank spot means there isn't information and aspot is put where there is information, as in a binary system.

Another method for printing dots on a page is to merely print the actualcharacters of the message and location in an ink which is not visible tothe human eye but which is visible to the camera. Then the camera readsthe characters using standard optical character recognition techniques.An ink which is visible in the near infrared might be used for thismethod. It will be apparent to one skilled in the art how to encode themessage and location on the page using a variety of methods so that itcan be made machine readable.

Referring now to the drawings, and in particular to FIG. 1, there isshown a page with a representation of an encoded message. In thisexemplary embodiment, the message corresponding to the printed documentis “ABC.” Fragments of the message, e.g., “A”, “B” and “C” are encodedat different pseudo-random locations on the page. For instance, the “A”portion of the message is encoded at points 101 and 103. The “B” portionof the message is located at points 105, 107 and 109. The “C” portion ofthe message is located at points 110, 113, 115 and 117. Absolutelocation information is also encoded on the printed page. Referringagain to FIG. 1, the upper left corner region is encoded with a “0,0” at119; a center region is encoded with a “1,1” at 121; etc.

In the exemplary embodiment, the fixed mapping between absolutelocations and message fragments appears in Table 1.

TABLE 1 Mapping between Absolute Locations and Message FragmentsAbsolute Location Fragment Position 0, 0 3 1, 0 1 2, 0 2 0, 1 2 1, 1 22, 1 3 0, 2 1 1, 2 3 2, 2 3

In one embodiment, the printed page is scanned by a mobile, possiblyhandheld, device which reads a swath of the printed page. Referringagain to FIG. 1, a swath is shown 150 by a dashed line. In thisexemplary embodiment, a camera or scanner is moved across the page inthe path indicated by the dashed lines 150. For this movement, themessage fragments and absolute locations read would be (0,0), (1,1) andthen (1,0). While the fragments are read in the order of CBA, they aredecoded as ABC because each fragment is mapped to an absolute locationand the device reads the absolute location and decodes it using a tablesuch as TABLE 1, above.

When the page is scanned in its entirety, the scanning device will haveall of the message information at its disposal. If a portion of the pageis missing or damaged, the message is still often retrievable due to therepetition of message fragments A, B and C 101, 103, 105, 107, 109, 110,113, 115 and 117 across the page. It will be apparent to one skilled inthe art that various schemes can be used to determine how frequently andat what resolution the message fragments appear on the printed page.There are obvious trade-offs regarding printer and scanner resolution,visibility to a human eye, range of motion for a handheld device toretrieve an entire message, etc. One skilled in the art will determinethe requirements necessary for the desired application and adjust thetrade-offs accordingly.

In the exemplary embodiment, the handheld device contains an imagingdevice capable of both reading the encoded information and ofdetermining the relative motion of the handheld device. One way toimplement this is by using a small digital camera and lens such that thecamera is focused on a small spot on the surface on which the devicerests. The camera may detect the encoded information by using standardcomputer vision techniques to recognize the printed dots in the image,and extract the information from their measured locations. The cameramay also detect the relative motion of the device by taking images ofwhatever surface the scanner happens to be on, and then using standardcomputer vision techniques, analyzing the changes in the images overtime to determine relative translation and rotation in the plane of thesurface (this is the similar to the way current optical mice operate).

As the device slides across a printed page, it can calibrate itsmeasured motion by comparing the measured relative motion to theobserved printed absolute locations. Then it can use those calibrationparameters, along with its measured motion, to compute a relativelocation. For example, say the device notices that every 10 cm ofhorizontal motion corresponds to 5 units of printed absolute location,then if you moved 30 cm to the right, it would compute a relative motionof 15 units to the right of where it started. Notice that so long as thedevice starts on the paper (to get an initial absolute location, andcalibrate itself), it may continue to provide relevant information wellbeyond the limits of the printed page. The imaging device, and thecomputation to analyze the images, may reside in separate modules, orthey may be implemented in a single self-contained module. Theimplementation of such systems will be apparent to one skilled in thestate of the art.

In the exemplary embodiment, the handheld device contains a display.That display may be implemented with existing Liquid Crystal Display(LCD) technology. This technology permits the display to be eithertransparent (in which case the displayed information may appear tooverlay whatever surface is beneath the display) or opaque (in whichcase it looks like a standard computer notebook display). Those familiarwith the state of the art should recognize that there are a number ofalternative display technologies suitable for such use, and the choicewill depend on a number of design trade-offs. It should also be apparentthat there are alternative methods of providing information for theuser. For example, the device may contain a printer. In one embodimentthe printer is a standard office printer, physically separate from thehandheld device. In another embodiment, the printer is a separate modulelocated within the handheld device. In an alternative embodiment, theprinter is capable of printing directly on the surface beneath thehandheld device, so that it prints information onto the same page fromwhich it is obtaining encoded positional information. In that case thedevice may rely entirely on motions of the user's hand, and need have nomoving parts (aside from the ink droplets). The device could alsocontain an audio or video playback module.

In the exemplary embodiment, the handheld device contains a userinterface. This may be implemented with push-buttons, dials or sliders.There are trade-offs in deciding how many controls, and of which types,should be included. Those familiar with the state of the art will beable to make such choices based on the particular applications intendedfor the device.

In the exemplary embodiment, the handheld device also includes acomputer. This computer recognizes messages detected by the scanner andperforms pre-coded actions which depend on the encoded message, thesensed location information (both absolute and relative), the state ofthe user interface (is the user pressing any button) and itspreviously-stored state. For example, the combination of this handhelddevice and a specially printed page may be used to plan a road trip. Inthis case, the printed page appears as a map to the human user, butcontains both a message and encoded location information. As the userslides the PDA across the map, the encoded message is extracted, and thecomputer recognizes that it refers to a particular map. Then it maycombine the absolute and relative location information to extract froman internal database a list of cities/sights related to the region ofthe printed page beneath the device. These may then be displayed for theuser. To plan the trip, the user moves the device over sights ofinterest and presses a “select” button when each is in the display. Eachtime this is done, the computer remembers the currently-displayedcity/sight information and its location. In this way, the combination ofthe printed page and the handheld device is used to quickly enter largeamounts of information in a very natural way. When done, the user slidesto a region of the map on which is printed “plan my route.” The computerrecognizes the combination of the message and this absolute location, soit plans a route through all the remembered locations. Now, it maydisplay the route for the user. Each time the device is moved, itdetermines the new location, and draws the portion of the routecorresponding to the portion of the map under the device. If the userwishes, they can now view the route by sliding back over the map—on thescreen they see the map below, with their route overlaid on top. Theuser may then continue to manipulate the on-screen map, merely bysliding the hand-held device on any convenient flat surface. In thatcase the computer notices that no absolute position is available, anduses the relative location information and the last known absoluteposition. The user also has the option to zoom in or out, changing thescale of the computer-generated display and also the relation betweenmotion of the device and motion of items in the display. It should beapparent to one skilled in the art that this relation may be computedsuch that it appears to the user as though the display were a windowover a virtual document, and where the computer zoom control has theeffect of enlarging or shrinking that virtual document.

In one embodiment, security or authorization information is containedwithin the message. When a document with security information encodedwithin the message is scanned, a user may be required to enter apassword, or the identity of the user may be assumed depending on theaccess device being used. For instance, the user may have already loggedon and identified oneself.

In an alternative embodiment, additional information may be encoded inthe message for marketing purposes. For instance, when sending eachcustomer a document, a company embeds the customer's ID number withineach printed copy. Then, when a device with access to the Internet isused on one of those documents, it (with the user's permission) notifiesthe company that a particular customer's printed copy is being accessedby a particular device. This, for example, enables a company to trackhow many different people use each particular printed copy.

In another embodiment, the message comprises an embedded sequence ofprocessing instructions, or macro. The macro uses one or both of theabsolute and relative location information as arguments. Once the macrois scanned and extracted, the processing instructions are interpreted,or executed, by the computing device. In an alternative embodiment usingmacros, the macro holds instructions to retrieve or modify data in atleast one storage device and uses that obtained information in itsexecution. For example, the system may store the state of the userinterface, or it may retrieve information for display from a database ona storage device.

In another embodiment, a device is used to retrieve or display moredetailed information related to an absolute location on the printedpage. Referring now to FIG. 2, a sales region 200 for a particularmarket is represented. Four distribution centers, or sales offices areshown 201, 203, 205 And 207. Suppose a salesperson has this printedpage, but not a printed version of the entire inventory list of eachcenter while on a sales call. If additional information is needed, itcan be produced in the field using an embodiment of the presentinvention. The salesperson has a specialized PDA with a camera orscanning device located typically on the underside. It will be apparentto one skilled in the art that the location of the camera or scanningdevice will depend on the ergo-dynamics of the handheld device. FIG. 3shows a specialized PDA 301 on top of the printed page with the salesregion 200.

Referring now to FIG. 3, the PDA 301 is placed over sales office 203,which happens to represent New York City, N.Y. The PDA will then displayinformation related to the region, such as the name of the sales office303, a volume of business 305, an average price, and a quantity ofcustomers 307. It will be apparent to one skilled in the art that thedisplayed information is dependent on the desired application and isdefined by an application programmer. In some embodiments, an action bythe user may be required, such as a mouse or button click/press, beforedisplaying the related information. This action will avoid visualconfusion as the display updates with varying related data continuouslyas the PDA or other device is moved across the printed page.

In another embodiment, the system is used to access updated calendarinformation, rather than related information. Referring now to FIG. 4,there is shown a representation of a calendar 400 for a selected week.The calendar has items stored for each day of the week. The calendar isaccurate at the time of printing, but may be updated a number of timeswithout reprinting. In some cases, the owner of the calendar will updatethe items, but have no access to a printer, for instance while onbusiness travel. Referring now to FIG. 5, the PDA 301 is placed over aday of the week, e.g., Thursday 501. While the printed version ofThursday's events 400 shows only one item 401, the version displayed onthe PDA 301 is updated to show four (4) items 503. Furthermore, if thedevice is now slid down off the printed calendar it will display thefollowing week, if slid further, it will display the week after that,and so on. The user may now dispense with the printed page entirely,zooming in and out using controls, and sliding up/down left/right tomove through different calendar entries, days, weeks, months, and years.It will be apparent to one skilled in the art that the entire user'scalendar may be accessed in this way and that the same techniques areapplicable to a range of other domains.

In another embodiment, there is a system where every salesperson has aspecialized PDA with a memory card in it. The memory card holds thecompany confidential information about the cost of each product andcurrent availability and other relevant data. The device has all of theinformation built into it and the salesperson just carries it aroundwith them. An advantage of this embodiment of the present invention isthat the salesperson gains access to information inside the device in away that's very natural. For example, the salesperson has a printedcatalog with a picture of every different product that they sell andthey flip open to the page where the particular product is that theircustomer is interested. Then the salesperson just runs across that pagewith their PDA and up on the screen of the PDA pops the most up-to-dateinformation, how or if any of those products are available and what thecurrent price is and what the backlog is, etc. The printed page servesas an interface for relatively static information and the PDA serves asyour interface for the more dynamic portion of the information.

In this scenario, a printed page might have one corner in which isprinted a blank box that said “availability” but doesn't have any numberin it. In the other corner a blank box is printed that says “costs.”When a user slides over the cost box with the PDA it shows the cost.When a user slides over the availability box, the PDA display shows thecurrent availability. In one embodiment, this information is maintainedlocally, within the PDA. An advantage of this embodiment is that nocommunication is necessary to other servers or systems in a network. Thesalesperson has another printed page, containing a grid. From left toright are the different industry sectors. Under each sector heading is acopy of the alphabet, from A at the top, to Z at the bottom. To accessinformation on a particular customer, the salesperson simply slidestheir PDA across the page to the sector they're interested in, and thenslides up and down to scroll through all their customers. They can getto any particular customer quickly by sliding straight to theappropriate letter of the alphabet. In this way, the salesperson is ableto navigate both the product database, and the customer database, usinga single device, and without any user action other than sliding thedevice on a printed page. Furthermore, since the message encoded on thepage is encoded redundantly, the salesperson need not carry the whole ofeach printed page with them. Once familiar with the customer lists andthe product catalogue, they could print a single page, with a smallportion of the customer list, and a small portion of the catalogue. Now,to access one or the other, they slide over that small portion, thenraise the device, place it on a table, and then continue to slide. Onthe screen, the result is exactly the same as when they had the wholeprinted page beneath the device.

The user (salesperson) has all the relevant data local to the printedpage. In other embodiments, the data is retrievable over a network, bywired or wireless methods. Other embodiments may store some datalocally, and some remotely.

A system 600 utilizing an embodiment of the present invention is shownin FIG. 6. A storage or memory 601 holds a plurality of documents and/orrelated data. The storage is connected to a printing device 605,typically through a CPU or other computing device 603. In someembodiments, the printing device has an imbedded processor and accessesthe storage 601 directly. The printing device is capable of printingdocuments from the storage encoded with message and absolute locationinformation 651 on a page 650. It will be apparent to one skilled in theart that the specifications of this printing device are dependent on themethod selected for encoding the information. For instance, if it isdesired that the address be invisible to the naked eye, the printingdevice 605 might use a special ink. Various resolutions may beimplemented based on trade-offs, as discussed above.

In one embodiment, a handheld device comprises a CPU 610, storage 611,user interface 612, display 613, an image sensor 613, and an imageanalyzer 614. The image sensor takes images of the surface on which thedevice is located. The image analyzer, analyzes those images to extracta message and absolute location (when the handheld device is over aprinted document 650) and relative motion (regardless of the surface onwhich the device is located). When a message is recognized by the imageanalyzer, it alerts the CPU 610, which looks up the message in itsstorage 611, and performs the appropriate pre-programmed action(s). Theuser may alter those actions using the user interface 612, and mayobserve the results or side effects by viewing the display 613.

In some embodiments, the storage 611 may be supplemented or replaced byremote storage 601 via a remote connection 607. The connection to remotestorage 601 can be via a local area network (LAN), wide area network(WAN), global distributed network, intranet, extranet or wirelessnetwork.

In some embodiments the various components may not all be physicallyconnected, but may reside in separate containers connected via wired orwireless means using dedicated or shared connections. For example theimage sensor could be located in a pen, while the image analyzer, CPUand display were located in a PDA.

FIG. 7 shows a flow diagram which describes a method for using anembodiment of the present invention. A document is printed in block 701using a special printer, where the document is encoded with message andlocation information, as discussed above. This document will typicallyhave useful data imprinted on it in addition to the message and locationinformation. If a user desires to interact with the printed document,then they slide the imaging device across it, in block 702. As thedevice moves, it continuously computes relative motion in block 703.

While the device is over the printed page, the image analysis systemdetects the presence of the encoding and extracts a fragment of themessage, and an absolute location from the image in block 704.

As the device moves across the page, more and more of the message iscollected, until the entire message has been accumulated. Adetermination is made as to whether the entire message has beencollected in block 705. If the entire message has been collected, thesystem retrieves the pre-coded action corresponding to that particularmessage in block 706.

In cases where the device is able to extract the absolute locationinformation in block 704, it uses that knowledge, in block 707 tocalibrate the measured relative motion. The last-known absolute locationis used with the measured relative motion to compute a new location. Thepre-coded action is then executed based on the location computed, inblock 708.

Finally, the results of the pre-coded action are displayed for the userin block 709. The user may then continue to move the device, and thedisplay will continuously update.

Executing the pre-coded action may require the device to retrieverelated data from a local or remote location based on the message andapplication. If the message is defined with security or authorizationlevels, the user is authenticated prior to the display or output of anydata. It will be apparent to one skilled in the art that any of avariety of authentication methods, now known or to be invented, may beused to enable this functionality.

The terms and descriptions used herein are set forth by way ofillustration only and are not meant as limitations. Those skilled in theart will recognize that many variations are possible within the spiritand scope of the invention as defined in the following claims, and theirequivalents, in which all terms are to be understood in their broadestpossible sense unless otherwise indicated.

1. A system for using a printed document encoded with a message,comprising: a movable image sensor that collects images of portions ofthe printed document, each portion being encoded with (1) an absolutelocation within the printed document and (2) a fragment of the message,wherein a known mapping exists between the position of each fragment andthe corresponding absolute location; and an image analyzer coupled tothe image sensor to determine relative motion of the image sensor andextract absolute locations and fragments of the message from the images,wherein the image analyzer extracts the message from the fragments usingthe known mapping.
 2. The system as recited in claim 1, wherein themessage is of variable size.
 3. The system as recited in claim 1,wherein the image analyzer determines the relative motion of the imagesensor by measuring changes in successive images such that the relativemotion can still be extracted even when the image sensor is not over theprinted document.
 4. The system as recited in claim 1, wherein theprinted document is selected from a group comprising a map, a calendarpage, a catalog, a customer list, and an index.
 5. The system as recitedin claim 1, further comprising a computing module that performs apredefined action in response to the extracted message and at least oneof (1) the relative motion of the image sensor and (2) the absolutelocations within the printed document.
 6. The system as recited in claim5, wherein the predefined action is selected from at least one of thefollowing: retrieving information from an information store; changingthe internal state of the computing module; storing information in aninformation store; and retrieving and executing a macro, wherein themacro comprises a sequence of processing instructions which uses atleast one of the absolute locations, the relative location, and theinternal state of the computing device.
 7. The system as recited inclaim 5, wherein the encoded message further comprises securityinformation, and wherein the predefined action is authenticated usingthe security information before being performed.
 8. The system asrecited in claim 5, further comprising at least one output device forshowing results or side-effects of performing the predefined action,wherein each of the at least one output device is one of a type selectedfrom the group consisting of a printer, visual display, audio device,audio-visual device, and multi-media device.
 9. The system as recited inclaim 8, wherein at least one output device is a visual display, and theimage sensor and visual display are integrated as one physical unit,thereby allowing the display to appear as a window over the printeddocument.
 10. The system as recited in claim 9, wherein each pixel onthe visual display is either transparent or opaque, andcomputer-controlled.
 11. The system as recited in claim 8, wherein atleast one output device is a print-head, and the image sensor andprint-head are integrated as one physical unit, thereby allowing theprint-head to leave marks, under computer control, on a surface beingscanned by the image sensor.
 12. The system as recited in claim 5,wherein a zoom factor is used to modify the relative motion of the imagesensor.
 13. The system as recited in claim 5, further comprising a userinterface in communication with the computing module, wherein the userinterface is used to select or modify the predefined action to beperformed in response to the extracted message and at least one of (1)the relative motion of the image sensor and (2) the absolute locationswithin the printed document.
 14. The system as recited in claim 5,wherein the predefined action depends on at least one of an identity ofthe image sensor, an identity of the computing module, and an identityof a human holding the image sensor.
 15. A system for using a printeddocument encoded with a message, comprising: a movable image sensor thatcollects images of portions of the printed document, each portion beingencoded with (1) an absolute location within the printed document and(2) a fragment of the message, wherein a known mapping exists betweenthe position of each fragment and the corresponding absolute location;an image analyzer coupled to the image sensor to determine relativemotion of the image sensor and extract absolute locations and fragmentsof the message from the images; and a computing module that extracts themessage from the fragments using the known mapping and performs apredefined action in response to the message and at least one of (1) therelative motion of the image sensor and (2) the absolute locationswithin the printed document.
 16. The system as recited in claim 15,wherein the message is of variable size.
 17. The system as recited inclaim 15, wherein the printed document is selected from a groupcomprising a map, a calendar page, a catalog, a customer list, and anindex.
 18. The system as recited in claim 15, wherein the predefinedaction is selected from at least one of the following: retrievinginformation from an information store; changing the internal state ofthe computing module; storing information in an information store; andretrieving and executing a macro, wherein the macro comprises a sequenceof processing instructions which uses at least one of the absolutelocations, the relative location, and the internal state of thecomputing device.
 19. The system as recited in claim 15, wherein theimage analyzer determines the relative motion of the image sensor bymeasuring changes in successive images such that the relative motion canstill be extracted even when the image sensor is not over the printeddocument.
 20. The system as recited in claim 15, wherein the encodedmessage further comprises security information, and wherein thepredefined action is authenticated using the security information beforebeing performed.
 21. The system as recited in claim 15, furthercomprising at least one output device for showing results orside-effects of performing the predefined action, wherein each of the atleast one output device is one of a type selected from the groupconsisting of a printer, visual display, audio device, audio-visualdevice, and multi-media device.
 22. The system as described in claim 21,wherein at least one output device is a visual display, and the imagesensor and visual display are integrated as one physical unit, therebyallowing the display to appear as a window over the printed document.23. The system as described in claim 22, wherein each pixel on thevisual display is either transparent or opaque, and computer-controlled.24. The system as recited in claim 21, wherein at least one outputdevice is a print-head, and the image sensor and print-head areintegrated as one physical unit, thereby allowing the print-head toleave marks, under computer control, on a surface being scanned by theimage sensor.
 25. The system as recited in claim 15 wherein a zoomfactor is used to modify the relative motion of the image sensor.
 26. Amethod for using a printed document encoded with a message, comprising:collecting images of portions of the printed document by an imagesensor, each portion being encoded with (1) an absolute location withinthe printed document and (2) a fragment of the message, wherein a knownmapping exists between the position of each fragment and thecorresponding absolute location; determining relative motion of theimage sensor; extracting absolute locations and fragments of the messagefrom the images; reconstructing the message from the fragments using theknown mapping; and performing a predefined action in response to themessage and at least one of (1) the relative motion of the image sensorand (2) the absolute locations within the printed document.
 27. Themethod as recited in claim 26, wherein the message is of variable size.28. The method as recited in claim 26, wherein the predefined action isselected from at least one of the following: retrieving information froman information store; changing the internal state of the computingmodule; storing information in an information store; and retrieving andexecuting a macro, wherein the macro comprises a sequence of processinginstructions which uses at least one of the absolute locations, therelative location, and the internal state of the computing device. 29.The method as recited in claim 28, wherein changes to the internal stateof the computing module are indicated by entering input using a userinterface, the user interface being in communication with the movabledevice, the changes to the internal state thereby influencingperformance of subsequent actions.
 30. The method as recited in claim28, further comprising: extracting an identifier from the encodedmessage; and recording the identifier and corresponding usageinformation in the information store, wherein the corresponding usageinformation comprise at least one of a device identifier for the imagesensor, an identifier for a user of the image sensor, a description ofthe predefined action to be performed, and a time at which thepredefined action is performed.
 31. The method as recited in claim 30,wherein information extracted from the information store is furtherbased on the extracted identifier.
 32. The method as recited in claim26, wherein determining relative motion of the image sensor furthercomprises measuring changes in successive images such that relativemotion can still be extracted even when the image sensor is not over theprinted document.
 33. The method as recited in claim 26, wherein theencoded message further comprises security information, and wherein thestep of performing the predefined action is preceded by a step ofauthenticating the predefined action using the security information. 34.The method as recited in claim 26, further comprising showing results orside-effects of performing the predefined action on at least one outputdevice, wherein each of the at least one output device is one of a typeselected from the group consisting of a printer, visual display, audiodevice, audio-visual device, and multi-media device.
 35. A method formonitoring the use of printed documents, said method comprising stepsof: encoding a customer identification mark on a printed document, theprinted document being further encoded with fragments of a messagedistributed across a plurality of locations on the printed document, thefragments being correlated with an encoded absolute location within theprinted document; and determining identification of the image sensorfrom which a request for information is originated, the informationrequest being determined by a scanning of a portion of the printeddocument by an image sensor, the image sensor determining a relativelocation on the portion of the printed document corresponding torelative motion of the image sensor, and the requested information beingrelated to the scanned portion of the printed document.
 36. The methodas recited in claim 35, further comprising the step of correlating theidentification of the image sensor with a corresponding user.
 37. Themethod as recited in claim 36, further comprising assembling therequested related information based on the corresponding user.
 38. Themethod as recited in claim 37, further comprising sending thecorresponding user the requested related information.